Nutrition Nuts and Bolts

By Shelly Najjar

I know someone who eats something called Bran Buds. It’s “good for you”, but I would never eat it. Why? Because besides looking like cat food, it doesn’t taste good. I would rather get my fiber from things I enjoy eating. Below is information about what fiber is, what it does, and where you can find it.

What is fiber?

Short answer: Fiber is a bunch of indigestible carbohydrates.
Longer answer: Fiber is a bunch of different types of indigestible carbohydrates that may do slightly different (but good) things in the body. It occurs naturally in many foods like fruits and vegetables, but also can be added to others to increase the nutritional benefit.

What does it do?

The Academy of Nutrition and Dietetics (AND) says a lot about fiber and its benefits. Here are a few things from them, with interpretive comments.

Populations that consume more dietary fiber have less chronic disease. […] High-fiber diets provide bulk, are more satiating, and have been linked to lower body weights. (Taken from the 2008 position paper on the health benefits of fiber)

Statistically speaking, people who eat more fiber don’t get chronic diseases as often. Eating what is considered a “high-fiber diet” (25-35g fiber each day) makes your bowel movements larger, makes you feel fuller, and may have some connection to weighing less.

Fiber is known for its benefits for your digestive system and its role in colon cancer prevention, and fiber is good for the heart, too.

Years of research suggest soluble fibers in beans, psyllium, oats, flaxseed and oat bran help lower blood cholesterol levels for some people. (Taken from from a previous nutrition tip of the day from the AND, archived by the U of Colorado, Colorado Springs)

Fiber “cleans out the colon” (colon=large intestine) (there’s a reason some people call it “Nature’s Broom”). People who eat more fiber reduce their risk for colon cancer. Soluble fiber (a type of fiber that can absorb water and other fluids) can lower blood cholesterol for certain people.

How does it work?

Bigger Bowel Movements: There are different kinds of fiber, and they all look different at a molecular level, kind of like branches. Things like bits of food, etc. get caught in those branches and don’t get absorbed by the small intestine. They go to the large intestine, with all that indigestible fiber, which has also absorbed a lot of water.

When we can’t digest something, the naturally occurring bacteria in the intestine eat what they like of the left over food. They break down the fiber and other things trapped in those “branches” and produce gasses (That’s why some fiber-rich foods make you gassy). All the rest of the indigestible stuff, plus the water and gas, takes up more room (is bigger) than the bowel movement that would have been made otherwise.

Feel Fuller: Remember how some fibers can absorb water? When they do, they expand. Things that take up more room in your stomach make you feel full.

Weighing Less: There are several reasons why this could happen. One: Fiber is found naturally in a lot of whole grains, fruits, veggies, etc. People who eat those things tend to weigh less. Two: Fiber, as mentioned before, cleans you out. That extra stuff sitting in there can weigh you down.

Cleaning Out That Colon: When things take up more room in the large intestine, it makes you want to “go”. All that fiber takes up a lot of room. As the colon (large intestine) stretches out, the little bits of excrement that have not yet been passed are pushed out by the bigger bowel movement. Also, water trapped by fiber is joined by additional water brought into the intestines (water is attracted to the byproducts of naturally occurring bacteria eating fiber we can’t digest). More water, softer bowel movements.

Reduced Colon Cancer Risk: The stuff that’s sitting in the large intestine (the leftover excrement that didn’t quite make it out) can be bad for you. The previous Cleaning Out That Colon section should explain the rest.

Soluble Fiber and Lower Cholesterol: The soluble fiber (the one that absorbs water and other fluids) can absorb bile. Bile is something your body produces to help with digestion. It always contains cholesterol. Bile gets recycled, so the cholesterol that was in it keeps getting used. The body can make more cholesterol, and more bile, but it’s efficient to recycle. So it does, but if you have high cholesterol, it might be better for the body to get rid of the excess. Soluble fiber soaks up bile (and the cholesterol in it), which means there is less to recycle, and the body produces new bile. However, it doesn’t seem to get as carried away, as long as you keep eating soluble fiber to keep it under control.

Less Chronic Disease: Keeping your weight under control and having normal cholesterol levels lessens your risk of chronic disease. In addition, many of the foods that have fiber have other things that decrease chronic disease risk.

Where is it found?

This was mentioned briefly before now, but here it is again. Fiber can be found in many foods. I understand that some people really like the flavor of Bran Buds, but since I’m not one of them, I’m going to list some foods that I like that also have fiber, and hope that you like them too.

• Fruits
• Vegetables
• Wild rice
• Oatmeal
• Baked beans

A Word of Caution

The AND is very clear about this and I want to be too:

Make changes slowly. Fiber helps move food through your intestine, but it takes time for your body to adjust to eating more. Adding too much too quickly may result in gas, bloating and cramping. (Taken from an article on Irritable Bowel Syndrome by the AND)

Don’t overdo your fiber intake. Eating more than 50 to 60 grams of fiber in a day can also lower the absorption of other vitamins and minerals that occurs during digestion. (Taken from a previous nutrition tip of the day from the AND, archived by the U of Colorado, Colorado Springs)

Drink plenty of fluids. Set a goal of at least 8 cups per day. You may need even more fluid as you eat higher amounts of fiber. Fluid helps your body process fiber without discomfort. (Taken from a High Fiber Foods list available through the AND’s Nutrition Care Manual)

Summary

• Fiber is indigestible carbohydrate found in naturally many foods like fruits, vegetables, beans, and whole grain products.
• Fiber has many benefits, including making you feel full, cleaning out the intestine, and decreasing colon cancer risk. It may also help you maintain a healthy weight.
• Soluble fiber is a type of fiber that can help lower cholesterol.
• Increase fiber gradually, or suffer consequences.
• Drink plenty of fluids with your fiber, to prevent discomfort.

Read More

• What is Fiber?
• Common questions about diet and cancer
• What are whole foods?
• What is a carbohydrate? (Carbs 101)

—

Shelly Najjar, MPH, RDN is a Registered Dietitian Nutritionist and wellness coach at Confident Nutrition. You can find her on Facebook, Twitter (@ShellyNajjar), and LinkedIn.